1. Field of the Invention
The present invention relates to novel pyrroloazepine derivatives, and more specifically to novel pyrroloazepine derivatives and salts thereof, said derivatives and salts having strong anti-.alpha..sub.1 action and anti-serotonin action but low toxicity and being useful as therapeutics for circulatory diseases such as hypertension and congestive heart failure, their preparation processes thereof and therapeutics for circulatory diseases, said therapeutics containing them as active ingredients.
2. Description of the Prior Art
Numerous substances have heretofore been known as drugs which act on the circulatory system. Among these, a variety of substances have been developed as antihypertensive drugs.
Of such antihypertensive drugs, .alpha..sub.1 -blockers represented by prazosin have such merits that (1) their antihypertensive action-is strong and sure, (2) they do not give adverse influence to the lipidometabolic and glycometabolic systems and (3) they can be easily used for hypertensives having complication. Their development is hence actively under way. Clinically-applied examples of such .alpha..sub.1 -blockers include bunazosin, doxazosin, terazosin and urapidil in addition to prazosin.
.alpha..sub.1 -Blockers are however accompanied by the drawback that they generally have side effects such as orthostatic disorder and reflex tachycardia, tend to induce orthostatic hypotension especially when administered to aged people and hence require attention.
As a drug having less tendency of inducing such side effects of .alpha..sub.1 -blockers, ketanserin having both anti-serotonin action and anti-.alpha..sub.1 action has been developed as a drug effective for senile hypertension and the like.
However, this ketanserin may not be able to exhibit, for example, sufficient hypotensive action in some instances, and its side effects to the central nervous system such as drowsiness and sedative action have posed problems.